A fixing device includes an endless fixing film that can revolve, a contact member that comes into contact with an inner peripheral surface of the fixing film, a pressure roller that press-contacts the fixing film from an outside of the fixing film toward the contact member to form a fixing nip area between the fixing film and the pressure roller, a heater that heats the fixing film, and a reflective member that reflects light emitted from the heater toward the fixing film. A protective member that allows irradiation of the light to the fixing film is provided between the heater and the fixing film.
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16. A fixing device comprising:
an endless fixing film that revolves;
a contact member that comes into contact with an inner peripheral surface of the fixing film;
a pressure roller that press-contacts the fixing film from outside the fixing film toward the contact member to form a fixing nip area between the fixing film and the pressure roller;
a heater that heats the fixing film;
a reflective member that reflects light emitted from the heater toward the fixing film; and
a protective member that allows irradiation of the light toward the fixing film provided between the heater and the fixing film, the protective member supported by the reflective member.
11. A fixing device comprising:
an endless fixing film that revolves;
a contact member that comes into contact with an inner peripheral surface of the fixing film;
a pressure roller that press-contacts the fixing film from outside the fixing film toward the contact member to form a fixing nip area between the fixing film and the pressure roller;
a heater that heats the fixing film;
a reflective member that reflects light emitted from the heater toward the fixing film; and
a protective member that allows irradiation of the light toward the fixing film provided between the heater and the fixing film, the protective member provided to face the fixing film by half a circumference or more of the fixing film.
1. A fixing device comprising:
an endless fixing film that revolves;
a contact member that comes into contact with an inner peripheral surface of the fixing film;
a pressure roller that press-contacts the fixing film from outside the fixing film toward the contact member to form a fixing nip area between the fixing film and the pressure roller;
a heater that heats the fixing film;
a reflective member that reflects light emitted from the heater toward the fixing film; and
a protective member that allows irradiation of the light toward the fixing film provided between the heater and the fixing film, the protective member provided closer to the fixing film than to the heater and is not in contact with both the heater and the fixing film.
2. The fixing device according to
3. The fixing device according to
4. The fixing device according to
6. The fixing device according to
7. The fixing device according to
8. The fixing device according to
9. The fixing device according to
12. The fixing device according to
13. The fixing device according to
14. The fixing device according to
17. The fixing device according to
18. The fixing device according to
19. The fixing device according to
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The present invention relates to a fixing device and an image forming apparatus including same, such as a copying machine, a multifunction peripheral, a facsimile device, and a printer.
A fixing device has been conventionally known, in which a contact member is brought into contact with the inner peripheral surface of an endless fixing film that can revolve, a fixing nip area is formed between the fixing film and a pressure roller by press-contacting the fixing film from the outside with the pressure roller, the fixing film is heated by a heater (heater lamp), and the light emitted from the heater is reflected by a reflective member toward the fixing film (see, for example, Japanese Unexamined Patent Application Publication No. 2011-028038 and Japanese Unexamined Patent Application Publication No. 2011-107252).
In such a fixing device, the heating source which is the heater, raises the temperature up to, for example, about 800° C., and thus it is necessary to prevent foreign matter from coming into contact with the heater.
In the fixing film, the end of the fixing film in the rotation axis direction is damaged due to the deviation in the rotation axis direction by the revolution movement. The inner surface of the fixing film is scraped by sliding with the contact member of the fixing film due to the pressure contact of the pressure roller, and foreign matter such as shavings of the fixing film is generated.
However, in the conventional configuration such as that described in Japanese Unexamined Patent Application Publication No. 2011-028038 and Japanese Unexamined Patent Application Publication No. 2011-107252, the heater is in an exposed state, and foreign matter such as a fragment of the fixing film may come into contact with the heater. In addition, when the fixing film is hard, it is possible that the heater is damaged by the impact of the fragment of the fixing film.
Therefore, an object of the present invention is to provide a fixing device and an image forming apparatus capable of effectively preventing foreign matter from coming into contact with a heater.
In order to solve the above problems, the fixing device according to the present invention includes an endless fixing film that can revolve, a contact member that comes into contact with an inner peripheral surface of the fixing film, a pressure roller that press-contacts the fixing film from an outside of the fixing film toward the contact member to form a fixing nip area between the fixing film and the pressure roller, a heater that heats the fixing film, and a reflective member that reflects light emitted from the heater toward the fixing film. A protective member that allows irradiation of the light to the fixing film is provided between the heater and the fixing film. In addition, the image forming apparatus according to the present invention includes the fixing device according to the present invention.
According to the present invention, it is possible to effectively prevent foreign matter from coming into contact with a heater.
Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In the following description, the same components are designated by the same reference numerals. Their names and functions are the same. Therefore, the detailed description of the same components will not be repeated.
As illustrated in
In the photoreceptor drum 10, a substrate 11 is rotatably supported by a main body frame (not illustrated) of the image forming apparatus 100, and is rotationally driven by a driver (not illustrated) about a rotation axis y in a predetermined first rotation direction G1 (clockwise in the drawing).
The charging device 90 includes a charging member 91. The charging member 91 uniformly charges the surface 10a of the photoreceptor drum 10 to a predetermined potential by a high voltage applying device 92. In this example, the charging member 91 is a charging roller, and is driven to rotate in a second rotation direction G2 with respect to the rotation of the photoreceptor drum 10. The charging member 91 may be an electrostatic charging charger.
The exposure device 30 repeatedly scans the light modulated on the basis of image information, on the surface 10a of the photoreceptor drum 10 to be rotationally driven, in the rotation axis y direction of the photoreceptor drum 10, which is the main scanning direction. The developing device 40 includes a developing roller 41 and a developing tank 42. The developing roller 41 supplies a developer DV to the surface 10a of the photoreceptor drum 10. The developing tank 42 houses the developer DV. The transfer device 50 includes a transfer member 51. The transfer device 50 applies a predetermined high voltage to a transfer nip area TN formed between the photoreceptor drum 10 and the transfer device 50 by a high voltage applying device 52. In this example, the transfer member 51 is a transfer roller and is driven to rotate in the second rotation direction G2 with respect to the rotation of the photoreceptor drum 10. The transfer member 51 may be a transfer charger.
The cleaning device 60 includes a cleaning blade 61 and a collection casing 62. The cleaning blade 61 removes the toner remaining on the surface 10a of the photoreceptor drum 10. The collection casing 62 houses the toner removed by the cleaning blade 61. The fixing device 200 includes a heating fixer 210 (heat fixing unit) and a pressure roller 220. The pressure roller 220 forms a fixing nip area FN together with the heating fixer 210. The detailed configuration of the fixing device 200 will be described later. In addition, the image forming apparatus 100 further includes a housing 80 that houses the respective components of the image forming apparatus 100.
Fixing Device
As illustrated in
The heating fixer 210 includes the fixing film 211 (see
The pressure roller 220 press-contacts the fixing film 211 from the outside toward the contact member 212 to form the fixing nip area FN between the fixing film 211 and the pressure roller 220.
The front upper frame 231 and the rear upper frame 241 revolvably support the front end and the rear end of the fixing film 211, respectively. The front upper frame 231 and the rear upper frame 241 are provided with a front support member 231b and a rear support member 241b including semi-ring-shaped sliding contact sections 231a and 241a, respectively. The sliding contact sections 231a and 241a are provided in such a manner that the sliding contact surface faces the side opposite to the fixing nip area FN. In the fixing film 211, the inside of both ends in the revolution axis ß (see
Examples of the fixing film 211 can include a fixing film in which a silicone rubber layer having a predetermined thickness (for example, approximately 100 to 300 μm) is formed on a metal or polyimide (PI) substrate having a predetermined thickness (for example, approximately 30 to 100 μm), and a fluororesin having a thickness (for example, approximately 20 to 30 μm) is further formed on the silicone rubber layer, specifically, a fixing film with a PFA tube on the upper layer of silicone rubber, or a fixing film with a fluororesin coated on the upper layer of silicone rubber.
As illustrated in
The heater 213 includes a heater lamp. As illustrated in
In this example, the reflective member 214 is a plate-shaped member (reflective plate) which is bent in such a manner that a portion in which the heater 213 is provided in the central portion in a short direction S orthogonal to the revolution axis ß direction is recessed, and that both ends of the plate-shaped member face the fixing nip area FN side. The reflective member 214 is formed of a metal material such as aluminum. The reflective member 214 is a mirror-finished surface on the heater 213 side. As a result, the light emitted from the heater 213 can be efficiently irradiated to the fixing film 211. The reflective member 214 is fixed to the holding member 215. As illustrated in
The holding member 215 is a sheet metal member obtained by bending both ends of a plate-shaped member in the short direction S orthogonal to the revolution axis β direction to the side opposite to the fixing nip area FN. The front end and the rear end of the holding member 215 are fixed to the front upper frame 231 and the rear upper frame 241 via a front holder 231e and a rear holder 241e, respectively.
The protective member 216 is provided between the heater 213 and the fixing film 211. The protective member 216 is a heat-resistant member having a configuration that allows the light emitted from the heater 213 and/or the light reflected from the reflective member 214 to be irradiated to the fixing film 211. The protective member 216 is provided with a large number of through holes 216a (see
Examples of the protective member 216 include a fiber shaped material woven into a mesh (netted) shape, a belt-shaped material that has been punched to provide a large number of through holes 216a, and a belt-shaped material that has been drilled (punched) to provide a large number of through holes 216a. Examples of the fiber shaped material include metal materials such as stainless steel (SUS) and aluminum. Examples of the belt-shaped material include metal materials such as stainless steel (SUS) and nickel. The thickness of the protective member 216 is preferably small, preferably about 0.5 mm or less.
The protective member 216 is provided in such a manner that a facing surface facing 216b facing the fixing film 211 faces the side opposite to the fixing nip area FN. Bent portions 216d are formed at both ends of the protective member 216 in the short direction S. The bent portions 216d are bent inward from both ends of the protective member 216 in the short direction S. The protective member 216 is formed in a semicircular dome shape. The bent portions 216d are fixed to the holding member 215 by the fixing member SC (screw) via the intervening members 215a. The radius of the protective member 216 can be about 30 to 40 mm. The protective member 216 is provided at a position concentric with the center of the semi-ring-shaped sliding contact sections 231a and 241a, with a radius smaller than the radius of the semi-ring-shaped sliding contact sections 231a and 241a by a predetermined distance or more. Here, the predetermined distance can be a distance that does not come into contact with the fixing film 211 even if the fixing film 211 revolves, for example, about 0.1 to 1 mm (for example, 0.8 mm).
As illustrated in
The examples of the pressure roller 220 can include a pressure roller in which an elastic member (sponge rubber such as silicone rubber or rubber member such as solid rubber) having a predetermined thickness (for example, about 6 mm) and a hardness of about 35 to 40 degrees is provided on a metal substrate such as aluminum and a fluororesin is formed on the elastic member, specifically, a pressure roller with a PFA tube provided on an elastic member. In this example, the fluororesin is provided in a passage area 6 (see
As illustrated in
The peeling member 270 is a peeling plate provided in the vicinity of the fixing film 211 on the downstream side of the fixing nip area FN in the first rotation direction G1 of the fixing film 211. As a result, it is possible to effectively prevent the recording medium P that has passed between the fixing film 211 and the pressure roller 220 from being wound around the fixing film 211.
According to the present embodiment, since the protective member 216 is provided between the heater 213 and the fixing film 211, it is possible to effectively prevent foreign matter from coming into contact with the heater 213. Moreover, since the protective member 216 allows the fixing film 211 to be irradiated with light, it is possible to suppress a decrease in the efficiency for heating the fixing film 211 by the heater 213.
In the present embodiment, the protective member 216 is provided with a large number of through holes 216a. In this way, the light emitted from the heater 213 and/or the light reflected from the reflective member 214 can be easily passed through with a simple configuration. Examples of the shape from a view of a plane of the through hole 216a can include a polygonal shape such as a quadrangle (diamond shape) and a hexagon (honeycomb shape), a circular shape, and an elliptical shape. Among them, the honeycomb structure can have the largest aperture ratio, and thus the amount of light that is emitted from the heater 213 and directly irradiated to the fixing film 211 can be increased. As the size of the through hole 216a becomes smaller, it becomes more difficult for foreign matter to enter the heater 213 side of the protective member 216. However, the amount of light that is emitted from the heater 213 and directly irradiated to the fixing film 211 decreases. Meanwhile, as the size of the through hole 216a becomes larger, it becomes easier for foreign matter to enter the heater 213 side of the protective member 216. However, the amount of light that is emitted from the heater 213 and directly irradiated to the fixing film 211 increases. Therefore, as the size of the through hole 216a (diameter for a circle, a maximum length for a non-circle), for example, about 0.5 mm to 1 mm can be exemplified.
In this example, the protective member 216 is formed in a mesh shape. In this way, the light emitted from the heater 213 and/or the light reflected from the reflective member 214 can be easily passed through with a simpler configuration.
In the example illustrated in
As in the example illustrated in
In this respect, in the example illustrated in
In the example illustrated in
In the example illustrated in
In the example illustrated in
In the present embodiment, at least a surface of the protective member 216 facing the fixing film 211 is formed of a high emissivity material having a higher emissivity than the emissivity of the reflective member 214. In this way, even if heat is absorbed on the opposite surface of the protective member 216 on the side opposite to the fixing film 211, the heat absorbed by the protective member 216 can be efficiently radiated to the fixing film 211 from the surface facing the fixing film 211 toward the inner surface of the fixing film 211 by the light emitted from the heater 213 and/or the light reflected from the reflective member 214. Examples of the high emissivity material include a material having an emissivity of 0.9 or more, specifically, an infrared radiation paint (manufactured by Okitsumo Incorporated).
When the protective member 216 comes into contact with the fixing film 211, at least one of the protective member 216 and the fixing film 211 is easily damaged. Moreover, heat unevenness is likely to occur in the fixing film 211 that is heated by the light emitted from the heater 213. Furthermore, when the protective member 216 comes into contact with the heater 213, the protective member 216 is damaged.
In this respect, in the present embodiment, the protective member 216 is in non-contact with both the heater 213 and the fixing film 211. In this way, the protective member 216 and the fixing film 211 can be made less likely to be damaged. Moreover, it is possible to suppress the occurrence of heat unevenness in the fixing film 211 that is heated by the light emitted from the heater 213.
When the protective member 216 is close to the heater 213, the protective member 216 is easily damaged by the heat of the heater 213.
In this respect, in the present embodiment, the protective member 216 is provided closer to the fixing film 211 than to the heater 213. In this way, it is possible to prevent the protective member 216 from being damaged by heat.
The protective member 216 may be provided so as to face the fixing film 211 by less than half a circumference of the fixing film 211. However, in this case, a phenomenon in which the temperature of the fixing film 211 locally becomes excessively higher than a specified temperature, so-called overshoot, is likely to occur. If so, inconvenience such as wrinkles of the fixing film 211 is likely to occur.
In this respect, in the present embodiment, the protective member 216 is provided so as to face the fixing film 211 by at least half a circumference of the fixing film 211. In this way, the occurrence of overshoot can be suppressed, and the occurrence of inconvenience such as wrinkles of the fixing film 211 thereby can be effectively prevented. Moreover, the fixing film 211 can be heated at a wide angle by the heater 213.
In the present embodiment, the heater 213 is provided between the reflective member 214 and the fixing film 211. In this way, the light reflected from the heater 213 to the reflective member 214 can be efficiently irradiated to the fixing film 211.
In the present embodiment, the heater 213 is provided on the side opposite to the fixing nip area FN with respect to the revolution axis ß of the fixing film 211. In this way, it is possible to perform a fixing process in the fixing nip area FN for the recording medium P in a state where the fixing film 211 is stably heated by the heater 213 and the protective member 216.
In the present embodiment, the protective member 216 is supported by the reflective member 214. In this way, the protective member 216 can be fixed to the reflective member 214 while the distance between the protective member 216 and the reflective member 214 is reliably maintained.
In the present embodiment, the reflective member 214 is supported by the holding member 215 that holds the contact member 212. In this way, the reflective member 214, the contact member 212, and the holding member 215 can be integrally formed. As a result, it is possible to compactify the configuration of the reflective member 214, the contact member 212, and the holding member 215 as a configuration in which the reflective member 214, the contact member 212, and the holding member 215 are mounted in the fixing film 211.
In the protective member 216, the bent portions 216d may be directly supported (fixed) at the holding member 215.
When the thickness of the protective member 216 is small, the efficiency for heating the fixing film 211 by the heater 213 is improved, but the strength of the protective member 216 is lowered.
In this respect, in the present embodiment, as illustrated in
In the first embodiment and the second embodiment, the protective member 216 is supported by the reflective member 214 by the bent portions 216d. However, when the protective member 216 is formed with the bent portions 216d, the strength of the protective member 216 is lowered at the bent portions 216d, and the protective member 216 is easily damaged.
In this respect, in a third embodiment, the protective member 216 is supported (fixed) at the reflective member 214 and/or the holding member 215 (both in the illustrated example) at a portion (arc portion) facing the fixing film 211. In this way, the protective member 216 can be supported at the reflective member 214 and/or the holding member 215 without providing the bent portions 216d. As a result, it is possible to eliminate the portion where the strength of the protective member 216 is lowered. The support pieces 214b constituting the reflective member 214 extend on both sides in the short direction S. The support pieces 214b are fixed to the protective member 216 and the holding member 215 by a fixer such as welding.
The present invention is not limited to the embodiments described above, and can be implemented in other various forms. Therefore, the embodiments are merely examples in all respects and should not be limitedly interpreted. The scope of the present invention is indicated by the claims and is not bound by the text of the specification. Furthermore, all modifications and changes belonging to the equivalent range of the claims are within the scope of the present invention.
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